It is well known to use hydrocyclones to separate particles of different sizes carried in a fluid stream. The particle separation achieved is governed by various factors including the dimensions of the hydrocyclone, the density of the suspension to be separated and its inlet pressure. To achieve some separations, it is necessary to use extremely small hydrocyclones which have a correspondingly small throughput. In order to achieve a commercially viable throughput, it is then necessary to employ a multitude of such hydrocyclones assembled in parallel. The most effective use of hydrocyclones is in separator assemblies with multi-stage operations. In the corn wet milling industry, hydrocyclones are used in starch wash operations, where multi-stage counter-current assemblies are preferred for purification of starch by removal of contaminants in the light phase, such as soluble and insoluble proteins, fine fibers, etc.